7) \(\dfrac{-2}{3}xy^2z\cdot\left(-3x^2y\right)^2\)
\(=\dfrac{-2}{3}xy^2z\cdot9x^4y^2\)
\(=\left(\dfrac{-2}{3}\cdot9\right)\left(x\cdot x^4\right)\left(y^2\cdot y^2\right)z\)
\(=-6x^5y^4z\)
Hệ số là: -6
Bậc là: 5+4+1=10
8) \(\left(-2xy^3\right)\cdot\dfrac{3}{8}\cdot\left(xz^2\right)^2\)
\(=\left(-2xy^3\right)\cdot\dfrac{3}{8}\cdot x^2z^4\)
\(=\left(-2\cdot\dfrac{3}{8}\right)\left(x\cdot x^2\right)y^3z^4\)
\(=-\dfrac{3}{4}x^3y^3z^4\)
Hệ số là: \(-\dfrac{3}{4}\)
Bậc là: 3+3+4=10
9) \(\dfrac{1}{4}\left(x^2y^3\right)^2\cdot\left(-2xy\right)\)
\(=\dfrac{1}{4}x^4y^6\cdot\left(-2xy\right)\)
\(=\left(\dfrac{1}{4}\cdot-2\right)\left(x^4\cdot x\right)\left(y^6\cdot y\right)\)
\(=-\dfrac{1}{2}x^5y^7\)
Hệ số: \(-\dfrac{1}{4}\)
Bậc: 5+7=12
`a, -2/3xy^2z.(-3x^2y)^2`
`= -2/3 xy^2z . 9x^4y^2`
`= -6x^5y^4z.`
Hệ số là `-6`.
Bậc là `10.`
`b, (-2xy^3).3/8.(xz^2)^2`
`= -3/4xy^3 . x^2z^4`
`= -3/4x^3y^3z^4`.
Hệ số: `-3/4`.
Bậc: `10`.
`c,1/4(x^2y^3)^2.(-2xy).`
`= -1/2x^4y^6.xy`
`= -1/2x^5y^7`.
Hệ số: `-1/2`.
Bậc: `11`.
